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1.
J Environ Manage ; 316: 115272, 2022 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-35580507

RESUMEN

Roads can block animal movement and reduce persistence of species living in road surroundings. Movement restrictions on local populations may even increase extinction risk of abundant small mammals. However, road verges (road managed area between the edge of the road and the beginning of private land) may provide refuge and corridors for small mammals when properly managed. Information on the effects of roads and roadside management on small-mammal movement is still scarce for low traffic roads (<20,000 vehicles per day) crossing well-preserved habitats. We aimed to fill this gap by comparing fine-scale movement patterns of wood mice (Apodemus sylvaticus) in a road and in a similar roadless area without management. Both areas consisted of a well-preserved Mediterranean agro-silvo pastoral system. We studied several movement patterns: road crossings, verge use, length, and direction of movement. Additionally, we assessed how roadside management, animals' sex and residency status, season and microhabitat affect movement at the road area. At the roadless area, we defined a virtual road and verges at equivalent locations to the road area for comparison purposes. We gathered capture-mark-recapture data for two years to characterize movement patterns. Wood mice tended to avoid the road by crossing it less often and moving away from it more frequently than from equivalent locations in the roadless area. Wood mice used road verges more frequently than virtual verges and moved more often parallel to the road than to the virtual road. Road crossings were more frequent after firebreak openings (strips of mowed land) in surrounding areas and near taller shrubs. Also, males used road verges more often than females. Differences on several movement patterns between areas and their trends within the road area can be explained mainly by the presence of the road and roadside vegetation management (e.g., firebreaks openings). We suggest roadside vegetation management practices (e.g., avoid land mowing; maintain vegetation strips) to promote the role of verges as refuges and/or corridors for small mammals.


Asunto(s)
Ecosistema , Mamíferos , Animales , Ratones
2.
J Environ Manage ; 318: 115450, 2022 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-35738124

RESUMEN

Ecological restoration has the potential to accelerate the recovery of biodiversity and ecosystem services in degraded ecosystems. However, current research queries whether active restoration is necessary. We evaluated plant-pollinator networks during spring at replicated sites within an actively restored quarry, at abandoned quarries undergoing spontaneous restoration, and within a natural reference area, to compare pollinator community composition and function. Overall, we aimed to assess which approach is more effective in rehabilitating pollination networks. We found that while both approaches allowed for the restoration of pollination function, active restoration provided faster recovery: pollination network structure was more similar to the reference ecosystem after 20-30 years of active restoration, than 40 years of natural succession in spontaneously restored areas. Different restoration approaches sustained distinct pollinator communities providing a similar service in different areas: honey bees played an important role in the natural area, bumblebees in the abandoned quarries and wild bees in the restored sites, suggesting a possible conflict between diverse wild bee communities and honey bee homogenized pollinator communities. In quarries, flower resource availability and diversity influenced networks' structural properties by constraining species interactions and composition. In spontaneously restored areas a rich herbaceous layer of ruderal species from early successional stages buffered against the shortage of flower resources at critical periods. Active restoration, though effective, should include practices that consider wild bee communities and mitigate flower resource scarcity. The use of "bridging" plants that flower in different periods, should be considered in active restoration programs to enhance the pollinator community.


Asunto(s)
Ecosistema , Polinización , Animales , Abejas , Biodiversidad , Flores , Insectos , Plantas
3.
J Environ Manage ; 277: 111412, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33038670

RESUMEN

Wildlife roadkill hotspots are frequently used to identify priority locations for implementing mitigation measures. However, understanding the landscape-context and the spatial and temporal dynamics of these hotspots is challenging. Here, we investigate the factors that drive the spatiotemporal variation of bat mortality hotspots on roads along three years. We hypothesize that hotspot locations occur where bat activity is higher and that this activity is related to vegetation density and productivity, probably because this is associated with food availability. Statistically significant clusters of bat-vehicle collisions for each year were identified using the Kernel Density Estimation (KDE) approach. Additionally, we used a spatiotemporal analysis and generalized linear mixed models to evaluate the effect of local spatiotemporal variation of environmental indices and bat activity to predict the variation on roadkill hotspot locations and to asses hotspot strength over time. Between 2009 and 2011 we conducted daily surveys of bat casualties along a 51-km-long transect that incorporates different types of roads in southern Portugal. We found 509 casualties and we identified 86 statistically significant roadkill hotspots, which comprised 12% of the road network length and contained 61% of the casualties. Hotspots tended to be located in areas with higher accumulation of vegetation productivity along the three-year period, high bat activity and low temperature. Furthermore, we found that only 17% of the road network length was consistently classified as hotspots across all years; while 43% of hotspots vanished in consecutive years and 40% of new road segments were classified as hotspots. Thus, non-persistent hotspots were the most frequent category. Spatiotemporal changes in hotspot location are associated with decreasing vegetation production and increasing water stress on road surroundings. This supports our hypothesis that a decline on overall vegetation productivity and increase of roadside water deficit, and the presumed lower abundance of prey, have a significant effect on the decrease of bat roadkills. To our knowledge, this is the first study demonstrating that freely available remote sensing data can be a powerful tool to quantify bat roadkill risk and assess its spatiotemporal dynamics.


Asunto(s)
Quirópteros , Animales , Animales Salvajes , Ecosistema , Portugal , Análisis Espacio-Temporal
4.
J Environ Manage ; 284: 112066, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33561758

RESUMEN

Local species assemblages are likely the result of habitat and landscape filtering. However, there is still limited knowledge on how landscape functional connectivity complements habitat attributes in mediating local species assemblages in real-world fragmented landscapes. In this study, we set up a non-manipulative experimental design in a standard production forest to demonstrate how functional connectivity determines the spatial distribution of a bird community. We test single- and multispecies spatially explicit, landscape functional connectivity models framed within the circuit theory, considering also patch attributes describing habitat size and quality, to weight their effects on species occurrence and community assemblage. We found that single-species functional connectivity effects contributed positively for occurrence of each species. However, they rarely provided competing alternatives in predicting community parameters when compared to multispecies connectivity models. Incorporating multispecies connectivity showed more consistent effects for all community parameters, than single-species models, since the overlap between species' dispersal abilities in the landscape shows poor agreement. Habitat size and quality, though less important, were also determinant in explaining community parameters while possibly relating to the provision of suitable nesting and foraging conditions. Both habitat and landscape filters concur to govern community assembly, though likely influencing different processes: while landscape connectivity determines which species can reach a patch, habitat quality determines which species settle in the patch. Our results also suggest that surrogating multispecies connectivity from single species has potential to source bias by assuming species perceive landscape and its barriers similarly. Inference on this issue must be gathered from as much species as possible.


Asunto(s)
Aves , Ecosistema , Animales , Bosques
5.
J Environ Manage ; 298: 113472, 2021 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-34365186

RESUMEN

Quarrying activities cause profound modifications on ecosystems, such as removal of vegetation cover, biodiversity loss and depletion of ecosystem services. Ecological restoration stands as a solution to revert such effects. Concomitantly, awareness is currently being given on ecosystem services and ecological processes to evaluate restoration efficiency. The objective of the study was to assess restoration success in a quarry subjected to restoration practices for the last 40 years involving the plantation of native Mediterranean vegetation and the non-native Aleppo pine Pinus halepensis. The study was carried out by assessing the effectiveness of seed dispersal service provided by birds in the restored quarry by comparing this service to neighbouring natural (shrubland) and other semi-natural areas (oak-pine mixed open and Aleppo pine forest) present at the landscape. For this purpose, we explored bird composition structure and seed dispersal networks using point counts and faecal samples of mist-netted birds. We also collected vegetation structure data and explored its effect on bird community composition. Our results showed that bird abundance in the restored quarry was significantly lower, and its bird community was compositionally different than natural shrubland and semi-natural areas. For instance, seed-dispersing birds, woody and shrub/ground foragers and partially migrators were the most affected groups at the restored area. Bird community composition and their traits were likely driven by vegetation characteristics, with higher native vegetation cover and fruit richness promoting higher bird abundance and Aleppo pine cover negatively influencing seed-dispersing birds. Concurrently, seed dispersal network in the restored quarry was less complex than in other areas. Seed dispersal services in the restored quarry were below the reported values for neighbouring natural and semi-natural areas and are likely driven by the low abundance of seed-dispersing birds. We consider that the causes affecting this group's low abundance can be related to revegetation measures favouring Aleppo pine, combined with a shallow soil depth and poor soil quality, which may have constrained native vegetation development. We conclude that seed dispersal services at the quarry are depleted, which may suggest a low restoration success concerning ecosystem functioning. Our results strengthen that quarry revegetation with non-native species must be avoided, since it alters bird community composition, and consequently, affects seed dispersal service provided by birds.


Asunto(s)
Dispersión de Semillas , Animales , Biodiversidad , Aves , Ecosistema , Bosques
6.
BMC Ecol ; 20(1): 2, 2020 01 03.
Artículo en Inglés | MEDLINE | ID: mdl-31900154

RESUMEN

BACKGROUND: In fragmented landscapes, natural and anthropogenic disturbances coupled with successional processes result in the destruction and creation of habitat patches. Disturbances are expected to reduce metapopulation occupancy for species associated with stable habitats, but they may benefit species adapted to transitory habitats by maintaining a dynamic mosaic of successional stages. However, while early-successional species may be favoured by very frequent disturbances resetting successional dynamics, metapopulation occupancy may be highest at intermediate disturbance levels for species with mid-successional habitat preferences, though this may be conditional on species traits and patch network characteristics. Here we test this 'intermediate disturbance hypothesis' applied to metapopulations (MIDH), using stochastic patch occupancy simulation modelling to assess when does intermediate disturbance favour metapopulation occupancy. We focused on 54 virtual species varying in their habitat preferences, dispersal abilities and local extinction and colonization rates. Long-term metapopulation dynamics was estimated in landscapes with different habitat amounts and patch turnover rates (i.e. disturbance frequency). RESULTS: Equilibrium metapopulation occupancy by late-successional species strongly declined with increasing disturbance frequency, while occupancy by early-successional species increased with disturbance frequency at low disturbance levels and tended to level-off thereafter. Occupancy by mid-successional species tended to increase along with disturbance frequency at low disturbance levels and declining thereafter. Irrespective of habitat preferences, occupancy increased with the amount of habitat, and with species dispersal ability and colonisation efficiency. CONCLUSIONS: Our study suggests that MIDH is verified only for species associated with mid-successional habitats. These species may be particularly sensitive to land use changes causing either increases or decreases in disturbance frequency. This may be the case, for instance, of species associated with traditional agricultural and pastoral mosaic landscapes, where many species disappear either through intensification or abandonment processes that change disturbance frequency.


Asunto(s)
Ecosistema , Modelos Biológicos , Dinámica Poblacional
7.
J Environ Manage ; 258: 110033, 2020 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-31929068

RESUMEN

Roads disrupt landscape connectivity for many terrestrial mammals. These infrastructures can be barriers to movement thereby threatening population persistence. Nonetheless, small mammals may use road verges as habitat or corridor, thus increasing migration across intensively managed landscapes. However, in well-preserved habitats where road verges show a similar vegetation structure to surrounding areas, their role is still unknown. Road verges would have an important role as fine-scale connectivity providers for small mammals in a well-preserved habitat depending on land management on road surroundings. We aimed to quantify the effects of road verges and paved lanes on the fine-scale landscape connectivity for the wood mouse (Apodemus sylvaticus) in a well-preserved Mediterranean woodland. Additionally, we assessed the impact on connectivity of vegetation cutting on verges and of management in surrounding areas (i.e. firebreaks, grazing, ploughing and cork stripping). We quantified connectivity using graph theory based on two years of capture-recapture data. We compared a set of connectivity metrics (derived from the probability of connectivity index) in a road area and in a virtual roadless scenario. We found that the presence of the road reduced overall fine-scale landscape connectivity, acting as a partial barrier for wood mice movement. However, verges had a key role in promoting movement on road surroundings. Vegetation cutting on verges, and land ploughing in the surrounding landscape were the only management activities compromising connectivity. Our study supports the already known role of road verges as habitat corridors for small mammals. However, it goes beyond existing knowledge by quantifying the connectivity enhancement provided by road verges and demonstrating that this role is highly relevant even in well-preserved landscapes. Therefore, our findings emphasize the critical role of road verges and suggest important management options to enhance landscape connectivity for small mammals.


Asunto(s)
Ecosistema , Mamíferos , Animales , Bosques , Ratones , Murinae
8.
J Environ Manage ; 247: 644-650, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31279141

RESUMEN

Road mortality is the most noticeable effect of roads on wildlife. Road verges may provide important refuges for small mammals and rabbits, particularly when roads cross intensive agricultural or grazed areas. In these circumstances, the increasing use of verges by prey species may attract predators to road surroundings increasing the risk of roadkill. The aim of this study was to quantify the role of prey availability (small mammals and rabbits) on predator road casualties, taking into account road and surrounding landscape characteristics. We analyzed this effect on different predator species, such as, snakes, owls and mammal carnivores. The study took place in a 10 km stretch of a National Road (EN4) in southern Portugal. Relationships among predator mortality and explanatory variables (prey abundance, landscape characteristics, and road verge features) were evaluated using Multivariate Redundancy Analysis (RDA) followed by a variation partitioning. Our results show that, although landscape features explained most of the mortality variation, the prey availability was also very important. Roadkills of Montpellier snake and Egyptian mongoose are strongly associated with wild rabbit abundance on verges, while mortality of stone marten, barn owl and tawny owl is related with wood mouse abundance, Mediterranean forest (montado) density, and verge shrub density. Implications for verge management and implementation of mitigation actions are discussed. We suggest vegetation removal in verges to decrease shelter and food availability for prey, and/or the promotion of habitat for prey in areas distant from roads.


Asunto(s)
Ecosistema , Estrigiformes , Animales , Egipto , Mamíferos , Ratones , Portugal , Conejos
9.
J Environ Manage ; 231: 878-885, 2019 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-30419443

RESUMEN

Along many roads worldwide, drainage culverts are the only structures wildlife can safely use to cross. However, culverts inundate and can become unavailable to terrestrial fauna during rainy periods. We conducted a field study over wet and dry seasons in southern Portugal to assess the effect of culvert flooding on crossings by medium-sized carnivores. We set up track stations inside 30 culverts along intermediate-level traffic roads to evaluate complete crossings (n = 1211) and used mixed-effects models to quantify the effects. Carnivores were more likely to cross and crossed more frequently if the culvert had a natural dry pathway at the time of the crossing. Carnivores were also more likely to cross culverts with streams running through them. Moreover, culverts with flowing streams during the wet season were still more likely to be crossed during the dry season when the streams were dry. The significance of the difference in crossing rates between wet and dry seasons was species-specific. Our study reveals that flowing water and dry pathways jointly contribute to promoting crossings by this carnivore community. Culverts including streams may act as a continuation of riparian corridors, being incorporated into carnivores' movement routes. Our results lend empirical support to recommendations advising the implementation of dry pathways to provide crossing paths. Interventions to offset the transient impacts of water flooding in new or existing culverts can be a cost-effective solution promoting connectivity across roads allowing movement of individuals.


Asunto(s)
Inundaciones , Ríos , Animales , Animales Salvajes , Portugal , Estaciones del Año
10.
Environ Manage ; 64(3): 329-343, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31372805

RESUMEN

Functional connectivity modeling is increasingly used to predict the best spatial location for over- or underpasses, to mitigate road barrier effects and wildlife roadkills. This tool requires estimation of resistance surfaces, ideally modeled with movement data, which are costly to obtain. An alternative is to use occurrence data within species distribution models to infer movement resistance, although this remains a controversial issue. This study aimed both to compare the performance of resistance surfaces derived from path versus occurrence data in identifying road-crossing locations of a forest carnivore and assess the influence of movement type (daily vs. dispersal) on this performance. Resistance surfaces were built for genet (Genetta genetta) in southern Portugal using path selection functions with telemetry data, and species distribution models with occurrence data. An independent roadkill dataset was used to evaluate the performance of each connectivity model in predicting roadkill locations. The results show that resistance surfaces derived from occurrence data are as suitable in predicting roadkills as path data for daily movements. When dispersal was simulated, the performance of both resistance surfaces was equally good at predicting roadkills. Moreover, contrary to our expectations, we found no significant differences in locations of roadkill predictions between models based on daily movements and models based on dispersal. Our results suggest that species distribution models are a cost-effective tool to build functional connectivity models for road mitigation plans when movement data are not available.


Asunto(s)
Animales Salvajes , Ecosistema , Animales , Bosques , Portugal , Incertidumbre
11.
Oecologia ; 182(1): 253-63, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27167226

RESUMEN

According to ecological theory, the coexistence of competitors in patchy environments may be facilitated by hierarchical spatial segregation along axes of environmental variation, but empirical evidence is limited. Cabrera and water voles show a metapopulation-like structure in Mediterranean farmland, where they are known to segregate along space, habitat, and time axes within habitat patches. Here, we assess whether segregation also occurs among and within landscapes, and how this is influenced by patch-network and matrix composition. We surveyed 75 landscapes, each covering 78 ha, where we mapped all habitat patches potentially suitable for Cabrera and water voles, and the area effectively occupied by each species (extent of occupancy). The relatively large water vole tended to be the sole occupant of landscapes with high habitat amount but relatively low patch density (i.e., with a few large patches), and with a predominantly agricultural matrix, whereas landscapes with high patch density (i.e., many small patches) and low agricultural cover, tended to be occupied exclusively by the small Cabrera vole. The two species tended to co-occur in landscapes with intermediate patch-network and matrix characteristics, though their extents of occurrence were negatively correlated after controlling for environmental effects. In combination with our previous studies on the Cabrera-water vole system, these findings illustrated empirically the occurrence of hierarchical spatial segregation, ranging from within-patches to among-landscapes. Overall, our study suggests that recognizing the hierarchical nature of spatial segregation patterns and their major environmental drivers should enhance our understanding of species coexistence in patchy environments.


Asunto(s)
Arvicolinae , Ecosistema , Agricultura , Animales , Clima , Ambiente
12.
J Environ Manage ; 162: 87-95, 2015 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-26232568

RESUMEN

Although locating wildlife roadkill hotspots is essential to mitigate road impacts, the influence of study design on hotspot identification remains uncertain. We evaluated how sampling frequency affects the accuracy of hotspot identification, using a dataset of vertebrate roadkills (n = 4427) recorded over a year of daily surveys along 37 km of roads. "True" hotspots were identified using this baseline dataset, as the 500-m segments where the number of road-killed vertebrates exceeded the upper 95% confidence limit of the mean, assuming a Poisson distribution of road-kills per segment. "Estimated" hotspots were identified likewise, using datasets representing progressively lower sampling frequencies, which were produced by extracting data from the baseline dataset at appropriate time intervals (1-30 days). Overall, 24.3% of segments were "true" hotspots, concentrating 40.4% of roadkills. For different groups, "true" hotspots accounted from 6.8% (bats) to 29.7% (small birds) of road segments, concentrating from <40% (frogs and toads, snakes) to >60% (lizards, lagomorphs, carnivores) of roadkills. Spatial congruence between "true" and "estimated" hotspots declined rapidly with increasing time interval between surveys, due primarily to increasing false negatives (i.e., missing "true" hotspots). There were also false positives (i.e., wrong "estimated" hotspots), particularly at low sampling frequencies. Spatial accuracy decay with increasing time interval between surveys was higher for smaller-bodied (amphibians, reptiles, small birds, small mammals) than for larger-bodied species (birds of prey, hedgehogs, lagomorphs, carnivores). Results suggest that widely used surveys at weekly or longer intervals may produce poor estimates of roadkill hotspots, particularly for small-bodied species. Surveying daily or at two-day intervals may be required to achieve high accuracy in hotspot identification for multiple species.


Asunto(s)
Monitoreo del Ambiente/métodos , Encuestas y Cuestionarios , Anfibios , Animales , Animales Salvajes , Aves , Mamíferos , Vehículos a Motor , Portugal , Reptiles
13.
Cir Esp ; 92(1): 11-5, 2014 Jan.
Artículo en Español | MEDLINE | ID: mdl-24588016

RESUMEN

INTRODUCTION: Metastatic lymph node affectation is the main prognostic factor in localized lung cancer. Pathological study of the obtained samples even after an adequate lymphadenectomy, present tumoral relapses of 40% of stage I patients after oncological curative surgery. In this paper we have studied micrometastasis in the sentinel lymph node by molecular methods in patients with stage I lung cancer. MATERIAL AND METHODS: The sentinel node was marked by injecting peritumorally performed just after performing the thoracotomy with 2 mCi of nanocoloid of albumin (Nanocol®) marked with 99mTc in 0.3 ml. Guided with a Navigator® gammagraphic sensor, we proceeded to its resection. RNA of the tissue was extracted and the presence of genes CEACAM5, PLUNC and CK7 in mRNA was studied. RESULTS: Twenty nine 29 patients were included. Of the tested genes, CEACAM5 and PLUNC were the ones that showed a high expression in lung tissue. Of the 29 analyzed sentinel lymph nodes, 7 (24%) were positive in the molecular study. A positive sentinel lymph node was found in 4/7 adenocarcinomas and 3/12 squamous-cell tumors. Affected lymph nodes were: station 5 (1/3), station 7 (0/6), station 9 (0/1); station 10 (5/11); station 11 (1/1). CONCLUSIONS: Detection of sentinel node in patients with stage I lung cancer by marking with radioisotope is a feasible technique. The application of molecular techniques shows the tumoral affectation in cases staged as stage I.


Asunto(s)
Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/patología , Radiofármacos , Biopsia del Ganglio Linfático Centinela/métodos , Agregado de Albúmina Marcado con Tecnecio Tc 99m , Anciano , Femenino , Humanos , Neoplasias Pulmonares/genética , Masculino , Persona de Mediana Edad , Técnicas de Diagnóstico Molecular , Cintigrafía
14.
Sci Total Environ ; 927: 172356, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38614338

RESUMEN

Roads represent one of the main sources of wildlife mortality, population decline, and isolation, especially for low-vagility animal groups. It is still not clearly understood how wildlife populations respond to these negative effects over space and time. Most studies on wildlife road mortality do not consider the spatial and temporal components simultaneously, or the imperfect roadkill detection, both of which could lead to inaccurate assumptions and unreliable mitigation actions. In this study, we applied a multi-season occupancy model to a 14-year amphibian mortality dataset collected along 120 km of roads, combined with freely available landscape and remote sensing metrics, to identify the spatiotemporal patterns of amphibian roadkill in a Mediterranean landscape in Southern Portugal. Our models showed an explicit general decrease in amphibian roadkill. The Iberian painted frog (Discoglossus galganoi) experienced roadkill declines over time of ∼70 %, while the spiny common toad (Bufo spinosus) and the fire salamander (Salamandra salamandra) had a loss of nearly 50 %, and the Southern marbled newt (Triturus pygmaeus) had 40 %. Despite the decreasing trend in roadkill, spatial patterns seem to be rather stable from year to year. Multi-season occupancy models, when combined with relevant landscape and remote sensing predictors, as well as long-term monitoring data, can describe dynamic changes in roadkill over space and time. These patterns are valuable tools for understanding roadkill patterns and drivers in Mediterranean landscapes, enabling the differentiation of road sections with varying roadkill over time. Ultimately, this information may contribute to the development of effective conservation measures.


Asunto(s)
Dinámica Poblacional , Animales , Portugal , Anfibios/fisiología , Monitoreo del Ambiente/métodos , Análisis Espacio-Temporal , Conservación de los Recursos Naturales , Transportes
15.
Nat Ecol Evol ; 8(2): 251-266, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38182682

RESUMEN

The biodiversity impacts of agricultural deforestation vary widely across regions. Previous efforts to explain this variation have focused exclusively on the landscape features and management regimes of agricultural systems, neglecting the potentially critical role of ecological filtering in shaping deforestation tolerance of extant species assemblages at large geographical scales via selection for functional traits. Here we provide a large-scale test of this role using a global database of species abundance ratios between matched agricultural and native forest sites that comprises 71 avian assemblages reported in 44 primary studies, and a companion database of 10 functional traits for all 2,647 species involved. Using meta-analytic, phylogenetic and multivariate methods, we show that beyond agricultural features, filtering by the extent of natural environmental variability and the severity of historical anthropogenic deforestation shapes the varying deforestation impacts across species assemblages. For assemblages under greater environmental variability-proxied by drier and more seasonal climates under a greater disturbance regime-and longer deforestation histories, filtering has attenuated the negative impacts of current deforestation by selecting for functional traits linked to stronger deforestation tolerance. Our study provides a previously largely missing piece of knowledge in understanding and managing the biodiversity consequences of deforestation by agricultural deforestation.


Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales , Filogenia , Bosques , Agricultura
16.
Zoolog Sci ; 30(4): 248-54, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23537234

RESUMEN

Rodent scent-marking is often used for territorial defence and self-advertisement, and both functions often entail the continuous scent-marking of a large area with high costs. In species with highly-fragmented populations and low density, in which the likelihood of social encounters is low, the costs of continuous scent-marking might exceed the associated fitness benefits; therefore, less intensive scent-marking only to signal presence to the opposite sex may be used. This hypothesis was tested in captivity with the Cabrera vole, a species with highly fragmented and low-density populations. Firstly, to assess the unknown scent-marking behaviour of the Cabrera voles, we conducted an assay wherein voles could scent-mark a clean substrate. Both sexes marked with urine and faeces, but never with anogenital secretions, and the amount of scent-marks was not different between sexes. In the subsequent assay, voles of each sex were given the choice of scent-mark on clean substrates or on substrates previously scent-marked by males or females. Both sexes marked with urine a larger area on substrates pre-marked by the opposite sex than on substrates pre-marked by the same-sex and clean substrates; however, no differences were found in the frequency of fecal boli deposited on the three types of substrate, and no anogenital secretions were found. The clear preference of receivers to scent-mark with urine the substrate pre-marked by the opposite sex strongly suggests that Cabrera voles use urine scent-marking for inter-sexual communication, probably to increase mate-finding likelihood, rather than for territorial defense and/or self-advertisement.


Asunto(s)
Arvicolinae/fisiología , Conducta Animal , Territorialidad , Animales , Demografía , Femenino , Masculino , Portugal , Glándulas Odoríferas , Factores Sexuales
17.
Sci Total Environ ; 869: 161705, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-36682566

RESUMEN

The effective management of species with small and fragmented populations requires an in-depth understanding of how the effects of human-induced habitat disturbance shape the structure and gene flow at fine spatial scales. Identification of putative environmental barriers that affect individual exchange among subpopulations is imperative to prevent extinction risks. Here, we investigated how landscape affects the gene flow and relatedness structure of a population of the endangered lesser horseshoe bat (Rhinolophus hipposideros). We also assessed the effects of sexbiased dispersal on genetic relatedness. We genotyped 287 bat samples collected across southern Portugal and developed resistance surfaces for landscape variables hypothesized to affect gene flow. Then, we used spatially explicit models to fit relatedness distance through the resistance surfaces. We found genetic evidence of sex-biased dispersal and identified a significant fine scale structuring in the relatedness regarding females, the philopatric sex. Males displayed uniform levels of relatedness throughout the landscape. The results indicated less relatedness between the female´ from roosts located on proximity of roads than in roosts away from roads. Also, when analysing the sexes together the relatedness on roosts separated by highway were subtly less related in comparison to those occurring on the same side. Roads seem to be major shapers of the contemporary population structure of females, regardless of being relatively recent structures in the landscape. Furthermore, the relatedness patterns detected suggested that high tree density among roosts and continuity of forest patches in broader surrounding areas, promotes the relatedness among individuals. Landscape heterogeneity among roosts slightly decreases genetic relatedness. Nevertheless, those relationships are still weak, suggesting that population structuring driven by those factors is slowly ongoing. Thus, effective management measures should focus on issues for promoting safe road passages and suitable habitat corridors, allowing for the exchange of individuals and gene flow among lesser horseshoe bat roosts.


Asunto(s)
Quirópteros , Humanos , Masculino , Animales , Femenino , Quirópteros/genética , Bosques , Ecosistema , Árboles , Flujo Génico , Genética de Población
18.
J Neurosurg Case Lessons ; 2(5)2021 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-36131580

RESUMEN

BACKGROUND: Spinal extradural hemangioblastomas (HBs) are quite uncommon, with most reported cases involving the thoracic and lumbar areas. Therefore, the presence of a dumbbell-shaped pure extradural cervical HB is exceptional, making preoperative diagnosis particularly challenging. OBSERVATIONS: The authors report a case of a 27-year-old woman who presented to their outpatient clinic with progressive cervicobrachialgia and numbness in the left arm. Magnetic resonance imaging showed a C5-6 intradural extramedullary lesion, and, despite some atypical features, the diagnosis of a possible neurogenic tumor was made. A multidetector computed tomography scan and angiography confirmed the expansion and remodeling of the left neural foramen as well as the highly vascularized nature of the mass. Preoperative embolization of the lesion was performed. Complete tumor resection was accomplished, followed by a C5-6 posterior fusion. Histopathology and immunohistochemistry revealed an HB. LESSONS: HBs should be considered among the differential diagnosis of cervical extradural tumors. Exhaustive preoperative workup and surgical planning are decisive in order to attain gross-total resection with favorable outcomes.

19.
Surg Neurol Int ; 11: 468, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33500806

RESUMEN

BACKGROUND: Solitary fibrous tumors (SFTs) are benign tumors derived from mesenchymal tissues that predominantly occur in the pleura. Establishing the diagnosis of these very rare intramedullary spinal lesions, with no clear-cut pathognomonic radiographic characteristics, is particularly challenging. CASE DESCRIPTION: Two males, 30 and 41 years of age, presented with progressive cervical myelopathies attributed to a cervical intramedullary exophytic tumor with associated spinal cord edema. One patient showed that the lesion was highly vascularized. Both patients underwent surgical excision of firm, solid, focal, and, particularly in one of them, very vascular/hemorrhagic tumors; at surgery, there was some adherence between the tumors and the cord tissue, but gross-total resections were achieved in both cases, demonstrated on postoperative MR scans. Histological and immunohistochemical findings confirmed the diagnosis of SFT (WHO Grade I). After a 6-month postoperative period, both patients neurologically improved and had no MR evidence of tumor recurrence. CONCLUSION: Intramedullary cervical exophytic SFTs are extremely rare. Although these solid tumors may present with hemorrhagic features and at surgery demonstrate significant adherence to the pial/cord surface, complete surgical resections are feasible resulting in good outcomes.

20.
Sci Total Environ ; 660: 340-347, 2019 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-30640102

RESUMEN

The effects of roads on bats are still a poorly documented issue. Most of the available research focuses on large and high-traffic highways, while low-medium-traffic roads are often assumed to have negligible impacts. However, small roads are ubiquitous in landscapes around the world. We examined the effects of these roads, as well as habitat types, on the activity of three bat guilds (short-, mid- and long-range echolocators) and the most common bat species Pipistrellus kuhlii. We performed three bat acoustic surveys between May and October 2015, with these surveys being performed along twenty transects that were each 1000 m long and perpendicular to three roads with different traffic volumes. The surveys were performed in dense Mediterranean woodland ("montado") and open agricultural field habitats, which were the two dominant land uses. At each transect, bat activity was simultaneously registered at 0, 50, 100, 200, 500 and 1000 m from the road with the use of an ultrasound recorder. According to the generalized linear mixed effects models, the overall activity of bats and of the short- and mid-range echolocators increased with increased distance from the roads and was dependent on the surrounding habitats. In contrast, the long-range echolocators and P. kuhlii were more tolerant to road. Our results also show that the activity was higher in woodland areas, however road verges seem to be a significant habitat in an open agricultural landscape. The major negative effects extended to approximately 300 m from the roads in woodlands and penetrate further into the open field (>500 m). The management of roadside vegetation, combined with the bat habitat improvement in areas that are further from the roads, may mitigate the negative effects. To make road-dominated landscapes safer for bats, the transport agencies need to balance the trade-offs between habitat management and road kill risk.


Asunto(s)
Quirópteros/fisiología , Ecosistema , Conducta Alimentaria , Animales , Portugal
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